Techniques have been developed to localize and quantitate biologic tumor markers in the cells and sera of patients with urologic cancers. These markers include human chorionic gonadotropin, alphafetoprotein, pregnancy specific beta1 glycoprotein (SP1), different isoenzymes of lactic dehydrogenase (LDH), ABO(H) antigens, and steroid receptors. These markers have been correlated with the histology, grade, stage, and management of patients with urologic cancers. Experimental animal models of cancer induction for the kidney, bladder, prostate, and testis have also been developed. These animal models are being utilized to study the role of cytoreductive surgery, chemotherapy, and immunotherapy of these urologic cancers. Athymic mice have been utilized for xenografts of testicular tumor that produce markers. By utilizing specific antibody labeled with 131I, the role at radioimmunodetection and radioimmunotherapy is being investigated in testicular and prostatic cancer.